You overwhelmingly see 1280x720, 1920x1080, and 3840x2160, sometimes with a truncated height because of aspect ratio but usually advertised with the full height for consistency reasons.
There's barely any 2560x1440. Anyone going above 1080p goes directly to 4k.
Youtube is pretty much the only place I've ever seen 1440p encodes, and that's because they're super version-happy and make 20 different variants of a video.
If it's about finding 1440p that'd mainly be because it's not a common broadcast format to the best of my knowledge - I just don't see it about much.
Articles such as: https://en.wikipedia.org/wiki/4K_resolution
don't mention it as a broadcast format, and articles that are specific to 1440p: https://en.wikipedia.org/wiki/1440p
have it as :
As a graphics display resolution between 1080p and 4K, Quad HD is regularly used in smartphone displays, and for computer and console gaming.It's pretty much only available on original encodes, i.e. BluRay rips, this makes it a format that very rarely seen on currently airing shows, which are mostly webrips from official streaming platforms.
You'll often see it alongside the usual resolutions for movies that have since been released on disk.
The most recent entry is:
How To Train Your Dragon The Hidden World (2019) 2160p 4K BluRay 5 1-LAMA
Format : HEVC
Width : 3 840 pixels Height : 1 634 pixels
Display aspect ratio : 2.35:1
Near the top is a recent TV episode:
True Detective S04E04 Night Country Part 4 2160p MAX WEB-DL DDP5 1 DoVi x265-NTb
Format : HEVC
Width : 3 840 pixels Height : 1 920 pixels
Display aspect ratio : 2.000
What makes things problematic is the overbearing love for letterbox like aspect ratios, even pirates have standards and they're having to bundle a slew of aspect ratios together .. this comes from the production companies.